.footer {
  width: 100%;
  height: 50px;
  background-color: #f1f3f5;
  position: fixed;
  display: flex;
  bottom: 0;
  left: 0;

  .activa {
    color: red;
  }

  a {
    display: block;
    flex: 1;
    line-height: 50px;
    text-align: center;
  }
}
